This critical summary from the American Dental Association – Evidence-based Center (ADA-EBD) looks at a 2010 systematic review from Atieh et al. The aim of the review was to assess whether platform switching (the placement of a smaller diameter prosthetic component on a larger diameter implant fixture) improved survival rate and bone loss.

The commentator notes that, although the reviews used a sound methodological approach, only 10 small studies were included, 3 of these being controlled trials, the remainder being randomised controlled trials. The commentator highlighted issues raised by the reviewers regarding the bone height measurement. it was also noted that the longest study was only 5 years.

A more recent systematic review covering this topic has been published by Al-Nsour et al 2012. Their review included 9 studies ( 6 randomised controlled trials). They concluded:-

Based on the current evidence, the use of abutments with a smaller diameter than their corresponding implant platforms seems to exert beneficial effects on peri-implant marginal bone. Some potential confounding factors, for example, the apicocoronal position of implants in relation to crestal bone, the presence of various implant microtextures, the degree of platform switch, and the reliability of examination methods, should be considered when interpreting the present results.

Derek Richards is the Director of the Centre for Evidence-based Dentistry, Editor of the Evidence-based Dentistry Journal, Consultant in Dental Public Health with Forth Valley Health Board and Honorary Senior Lecturer at Dundee & Glasgow Dental Schools. He helped to establish both the Centre for Evidence-based Dentistry and the Evidence-based Dentistry Journal. He has been involved with teaching EBD and a wide range of evidence-based initiatives both nationally and internationally since 1994.